Now you've done it. As a proud fan of the metaphysical, I've spent a lot of time thinking about names for old souls (what I sometimes call 'expanded soul' types.) To me, the best old soul names are those with a lot of Pisces energy in them. Pisces letters are G, P, and Y. Bonus points for a meaning with spiritual or at least humanitarian significance. My suggestions:

Gabriel, (woman of god) Georgiana, (earth lover) Gwendolyn (white-browed--nothing special about the meaning, but it has 'extra' Pisces)